Wooden girder



mim, 2 um@ NVNT Ri WOODEN GIRDER Film June 28, 1920 Patented Feb. 2, 1926.

UNITED STATES' PATENT OFFICE.

WOODEN GIRDER..

Application led June 28,1920. Serial No. 392,556.

(GRANTED UNDER THE PRVISIONS 0F THE ACT 0F MARCH 3, 1921, 41 STAT. L., 1313.)

To all whom it may concern.'

Be it known that I, CLAUDIUS DORNIER, a. citizen of the German Empire, residing at Friedrichshafen-on-the-Bodensee, Germany, have invented certain new and useful 'Improvements in Wooden Girders (for which I have filed application in Germany, August 25. 1915, Patent No. 298,584), of which the following is a specification.

My invention refers to frame work girders and more especially to the construction of boom members for girders especially used in the construction of air craft, which are to be made as strong and at the same time as light as possible. In order to reduce their own weight as lmuch as possible in spite of 1 an increased resistance against forces acting from outside, especially bending forces, according to the mvention members are used, whlch due to their speclal design assisted by their material possess a high moment of-v inertia at a given Weight per unit of length, and which afford good connections for other structural parts.

Thus the obj ect of my invention is a boom member for wooden girder-s, especially suitable for the construction of air craft, in which the section of the boom member is composed of a core consisting of one or several 4divisions with rib-like longitudinal webs partly grooved for inserting branch bars and of a cap partly enclosing the webs like a mantle.`

In the drawings affixed to this specificar tion and forming art. thereof several modiications of a gir er embodying my invention are illustrated by way of example.

Fig. 1 is a cross section oi a flange member adapted to receive a single row of panel rods,

Fig. 2 is a similar view of a iange member with two rows of panel rods extending theretrom.v

Fig. 3 is a like view of a iange member differing from the one shown in Fig. 2 in that the rows of {iange rodsare set at an angle to one another.

Fig. 4 is a cross section of a. flange mem.- ber with three rows of panel rods associated therewith. f Fig. 5 is a like view -of a longitudinally divided flangemember and booms.

Fig. 'shows another modification of the divided fiange member shown in Fig. 5.

Fig. 7 is an elevation, and Fig. S is an end view of a girder comprising Bange members such as disclosed in Fig. 1. y

Figs. 9 and 10 are corresponding views of a girder having its Hange members shaped after theA manner of that shown in Fig. '2, and

Figs. 11 and 12 disclose in similar views a girder of triangular section having iange members such as illustrated in Fig. 6.

In the example according to Fig. 1 the boom or fiange member consists of a core 1 in one Apiece provided with three-ribs 2 enclosed by a cap 3 as by a mantle, while a fourth wider rib-shaped web 4 is grooved 70 longitudinally. The continuous groove thus formed serves to receive branch or web members 5, if e. g. a plane rigid frame is to be made similar to that shown in Fig. 7, in which two bars according to Fig. 1 are the 75 The ribs 2 and 4 preferablyarranged in the plane of the main forces give the single bar 1 high resistance against breaking, while cap 3 on the one hand prevents the single ribs from being damagedSO and on the other hand gives the sections a good shape as to its resistance to the air. Though these good qualities are to be found in a single bar and permit using it independentlyin many cases, they appear more espeoially in the case 'where several bars are united to form a girder.

For some purposes, a double row of web members are required, in which ca'se the core 11 according to Fig. 2 preferably nas 90 two ribs 14, each grooved on one side. vThe outside wall of the two continuous grooves thus obtained is formed by cap 13 reaching further down to match, which may consist of wood or of some other light and ,highly resistant material. In Figs. 9 and 10 a boxshaped girder is shown composed of such bars.

The most important application of these bars is that for booms of girders in space. A modification of a boom member for a triangular open 'frame work girder similar'to that in Figs. 11 and 12 isl shown in Fig. 3. Both bottom ribs 24 provided on the core 21 are arranged at thefrequired angle relatively to each other. Cap mat-ching the angular shape forms again the outer mantle. Instead of arranging the web bars in a continuous bond like that of Fig. 9, single cross webs of some well known kind may be used for reinforcing according to the example in Fig. 11.

The web or branch bars maybe connected with the boom at any anglerequired and more` than two bars may be joinedon as shown in Fig. 4. In this modification between two outside webs 34 branching olf at flat angles a third rib-like web 36is inserted. In those three groves three rows of webs 35 can tliusbe inserted e; g. for a quadrangular box girder '(not shown in the drawing), which is reinforced by a diagonal web. In a similar manner an open frameworkof every description can be made of boom members correspondingly chosen and any kind of web filling in use before now can be employedin it; The core need not absolutely consist of wood., The main thing is to use some material sufliciently light for making webs resist against buck# ling without overstepping the customary weight limit for air craft.

The cap may be connected with the core and equally the web with the boom mem# bers in several ways, e. g. by. means of wire nails, by gluing or screwing them together 1or in some other suitable manner. More than one kind of connections may be employed at the same time.

For a larger number of branches or, if the shape is not quite simple, the core is preferably made in more than one lpiece and the separate parts are united in some suitable way, eg. by a tongue-and-groove joint and by gluing them together. Thus the cores can be made especially strong, e

as the. small sections can be'easier ma cores compose sembled by means of a tongue and groove joint.

5, 6 and 11, a articular advantage of the dp of several pieces is that with open girders two parts'of the core connected by, a row of web bars form the booms of planeigirders. -The open girder can be constructed with theiraid in a very simple way by joining the boomsl of the girder parts-preferably provided with tongues 4and grooves vand by strengthening the resistance of each united boom member by a mantle# shaped cap.

I claim: 1.- A

ing along said members and a row of panel rods connecting said members and having their ends inserted in said grooved ribs.

2. A ,girder comprising in combination, non-metallic'boom members, a longitudinal grooved rib on said members, caps extending alongsaid members and a row of panel rods connecting said members and havin their ends inserted between said groove ribs and said vcaps.

3. A girder comprising in combination, non-metallic longitudinally divided boom members, a longitudinal grooved rib on each half of said members, caps extending along and uniting said divided boom members- 4and a row of panel rods connecting said As maybe gleaned 'especially vfrom Fig irder comprising in combination, nonmeta 11o boom members, a longitudmalA Igrooved r1b on said members, caps extendmembers and havingI their ends inserted in said grooved ribs.

In testimony whereof I aHiX my signature.

CLAUDIUS DORNIER. j 

